#include<bits/stdc++.h>
using namespace std;
#define int long long
const int MAX_SOM=100*1000+5,MAX_LOG=18,MAX_REQ=100*1000+5,DECA=(1<<17);
int nbSom,nbCheck,nbReq,idAre,coutArg,idSom,nbRest;
vector<int> adja[MAX_SOM];
int are[MAX_SOM][2];
int prof[MAX_SOM];
int pere[MAX_SOM][MAX_LOG];
int req[MAX_REQ][6];
int num[MAX_SOM];
int sousArbre[MAX_SOM][2];
vector<pair<int,int>> checkTri;
vector<int> reqDeb;
int cumu[2*DECA][2];
void DFS(int pos,int anci,int etage) {
if (prof[pos]==0) {
//cout<<pos<<" "<<anci<<" "<<etage<<endl;
pere[pos][0]=anci;
prof[pos]=etage;
idSom++;
num[pos]=idSom;
sousArbre[pos][0]=idSom;
for (int vois:adja[pos]) {
DFS(vois,pos,etage+1);
}
sousArbre[pos][1]=idSom;
}
}
int lca(int som1,int som2) {
if (prof[som1]>prof[som2]) {
swap(som1,som2);
}
for (int i=MAX_LOG-1;i>=0;i--) {
if (prof[pere[som2][i]]>=prof[som1]) {
som2=pere[som2][i];
}
}
if (som1==som2) {
return som1;
}
for (int i=MAX_LOG-1;i>=0;i--) {
if (pere[som1][i]!=pere[som2][i]) {
som1=pere[som1][i];
som2=pere[som2][i];
}
}
return pere[som1][0];
}
void ajout(int deb,int fin,int val,int idTab) {
if (deb==fin) {
cumu[deb][idTab]+=val;
}
else if (deb%2==1) {
cumu[deb][idTab]+=val;
ajout(deb+1,fin,val,idTab);
}
else if (fin%2==0) {
cumu[fin][idTab]+=val;
ajout(deb,fin-1,val,idTab);
}
else {
ajout(deb/2,fin/2,val,idTab);
}
}
int calcVal(int pos,int idTab) {
int somme=0;
while (pos!=0) {
somme+=cumu[pos][idTab];
pos/=2;
}
return somme;
}
void addAre(int i,int coeff) {
//cout<<i<<" : "<<sousArbre[are[checkTri[i].second][1]][0]<<" "<<sousArbre[are[checkTri[i].second][1]][1]<<endl;
ajout(DECA+sousArbre[are[checkTri[i].second][1]][0],DECA+sousArbre[are[checkTri[i].second][1]][1],checkTri[i].first*coeff,0);
ajout(DECA+sousArbre[are[checkTri[i].second][1]][0],DECA+sousArbre[are[checkTri[i].second][1]][1],coeff,1);
}
int calcDist(int r,int idTab) {
/*cout<<endl;
cout<<r<<" "<<idTab<<endl;
cout<<num[req[r][0]]<<" = "<<calcVal(DECA+num[req[r][0]],idTab)<<endl;
cout<<num[req[r][1]]<<" = "<<calcVal(DECA+num[req[r][1]],idTab)<<endl;
cout<<num[req[r][5]]<<" = "<<calcVal(DECA+num[req[r][5]],idTab)<<endl;*/
return calcVal(DECA+num[req[r][0]],idTab)+calcVal(DECA+num[req[r][1]],idTab)-2*calcVal(DECA+num[req[r][5]],idTab);
}
void calc(int debInter,int finInter,int posCour,vector<int> reqCour) {
if (reqCour.empty()) {
return;
}
int midInter=(debInter+finInter+1)/2;
if (finInter==-1) {
midInter=-1;
}
/*cout<<debInter<<" "<<finInter<<" "<<posCour<<" "<<midInter<<" : ";
for (int r:reqCour) {
cout<<r<<" ";
}
cout<<endl;*/
if (posCour<midInter) {
for (int i=posCour+1;i<=midInter;i++) {
addAre(i,1);
}
}
else {
for (int i=posCour;i>midInter;i--) {
addAre(i,-1);
}
}
/*for (int i=1;i<2*DECA;i++) {
cout<<cumu[i][0]<<" "<<cumu[i][1]<<" ";
}
cout<<endl;*/
if (debInter==finInter) {
for (int r:reqCour) {
//cout<<r<<" "<<calcDist(r,0)<<" "<<calcDist(r,1)<<endl;
req[r][4]=calcDist(r,1);
}
}
else {
vector<int> reqSous,reqSur;
for (int r:reqCour) {
//cout<<r<<" : "<<calcDist(r,0)<<endl;
if (calcDist(r,0)>req[r][3]) {
reqSous.push_back(r);
}
else {
reqSur.push_back(r);
}
}
calc(debInter,midInter-1,midInter,reqSous);
calc(midInter,finInter,midInter,reqSur);
}
if (posCour<midInter) {
for (int i=posCour+1;i<=midInter;i++) {
addAre(i,-1);
}
}
else {
for (int i=posCour;i>midInter;i--) {
addAre(i,1);
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>nbSom>>nbCheck>>nbReq;
for (int i=1;i<nbSom;i++) {
cin>>are[i][0]>>are[i][1];
adja[are[i][0]].push_back(are[i][1]);
adja[are[i][1]].push_back(are[i][0]);
}
DFS(1,0,1);
/*for (int i=1;i<=nbSom;i++) {
cout<<i<<" : "<<num[i]<<" "<<sousArbre[i][0]<<" "<<sousArbre[i][1]<<" "<<pere[i][0]<<" "<<prof[i]<<endl;
}*/
for (int j=1;j<MAX_LOG;j++) {
for (int i=0;i<=nbSom;i++) {
pere[i][j]=pere[pere[i][j-1]][j-1];
}
}
for (int i=1;i<nbSom;i++) {
if (prof[are[i][0]]>prof[are[i][1]]) {
swap(are[i][0],are[i][1]);
}
}
for (int i=0;i<nbCheck;i++) {
cin>>idAre>>coutArg;
checkTri.push_back({coutArg,idAre});
}
sort(checkTri.begin(),checkTri.end());
for (int i=0;i<nbReq;i++) {
cin>>req[i][0]>>req[i][1]>>req[i][2]>>req[i][3];
reqDeb.push_back(i);
req[i][5]=lca(req[i][0],req[i][1]);
}
calc(-1,nbCheck-1,-1,reqDeb);
for (int i=0;i<nbCheck;i++) {
addAre(i,1);
}
for (int i=0;i<nbReq;i++) {
nbRest=calcDist(i,1)-req[i][4];
//cout<<i<<" : "<<req[i][4]<<" "<<calcDist(i,1)<<" ";
cout<<max(req[i][2]-nbRest,(int)-1)<<"\n";
}
return 0;
}
